AGP is a different market. These are your best bet:
http://www.newegg.com/Product/Produc...82E16814102093 Radeon X1950 GT $130
http://www.newegg.com/Product/Produc...82E16814241041 Radeon X1950 Pro $150
http://www.newegg.com/Product/Produc...82E16814130076 GeForce 7600 GS $100
The one you listed is way overpriced. That card is only worth $100.
Any of these cards will run circles around your old one. They are undoubtedly better than your old card, but WoW running better is guess work -- it's largely a CPU-limited game, meaning your CPU has a much bigger impact on gameplay than the videocard. But that videocard you have is a real shitbox so if you have a decent CPU then your FPS should go up with these cards.